The Living World 6th Edition by George Johnson, Jonathan Losos,William Ober,Claire Garrison

تمرين 16

Your friend, Alex, just returned from a family trip to northern Michigan, where he visited a maple tree farm where they made maple syrup. On the maple trees, they made just one small hole (or two small holes on larger trees) and hung a bucket beneath to catch the sap. Why, he asks you, wouldn't they just make a cut completely around the tree and collect much more sap, much faster Why isn't this feasible